Allocation

Abstract

The last few years have seen major breakthroughs for both fundamental and astrophysics: in 2015 the gravitational waves from a merging binary black hole were detected for the first time. In August 2017, the merger of two neutron stars was detected for the first time: a one minute long "chirping" gravitational wave signal in the LIGO/VIRGO detectors was followed by electromagnetic emission from the same location all across the spectrum. This first "multi-messenger" detection has lead to major leaps forward in various fields, for example it has constrained the propagation speed of gravitational waves to an enormous precision, it showed that neutron star mergers cause gamma-ray bursts and that they are the major sources of the heaviest elements in the cosmos. For these and other reasons, this discovery was celebrated as the {\em Breakthrough of the year 2017} by the Science magazine.
The major aim of this application is the hydrodynamical modelling of neutron star mergers, their ejecta and their electromagnetic emission. To this end we are combining different hydrodynamic methodologies and codes: a Lagrangian Smooth Particle Hydrodynamics code (called MAGMA2; containing a variety of physics models such as nuclear equations of state or neutrinos) and a special-relativistic, adaptive mesh refinement (AMR) magneto-hydrodynamics code (called AMUN), that is ideal to study relativistic outflows.